Wildfires will get worse with climate change, not only endangering those near the blazes, but also threatening the health of millions of Americans from wildfire smoke that can drift hundreds of miles, according to a new report by the Natural Resources Defense Council.

As a result, communities must protect themselves from the health risks arising from exposure to wildfire smoke—including asthma attacks, pneumonia, and more serious chronic lung diseases. And the report, titled “Where There’s Fire, There’s Smoke,” suggests the country take action to curb the threat of climate change.

“There’s trouble in the wind: What blazes in Texas rarely stays in Texas. Wildfire smoke can pose serious health risks to people hundreds of miles away from the sources of fires,” said Kim Knowlton, a senior scientist in NRDC’s Health and Environment Program, who directed the analysis. “Wildfire smoke already clouds the skies of millions of Americans and because climate change will fuel more wildfires, that danger will rise. Communities need safeguards against this smoky peril, and our country needs standards to curb the unlimited carbon pollution from power plants that’s driving climate change.”

The study, based on 2011 data, found that the area affected by smoke is 50 times greater than the area burned by fire. About two-thirds of Americans—nearly 212 million people—lived in counties affected by smoke conditions in 2011.

The states with the greatest numbers of residents affected by wildfire smoke conditions for a week or longer in 2011, according to the report, were Texas, Illinois, Florida, Missouri, Georgia, Louisiana, Michigan, Alabama, Oklahoma and Iowa.

The report found that in 2011:
* Texas ranked 1st nationally because more than 25 million people lived in areas with wildfire smoke conditions for one week or more.
* Illinois ranked 2nd with 11.9 million residents in affected areas.
* Florida ranked 3rd with 11.2 million residents in affected areas.
* Missouri ranked 4th with 5.9 million residents in affected areas.
* Georgia ranked 5th, with 5.7 million residents in affected areas.
* Louisiana ranked 6th, with 4.5 million residents in affected areas.
* Michigan ranked 7th, with 3.93 million residents in affected areas.
* Alabama ranked 8th, with 3.92 million residents in affected areas.
* Oklahoma ranked 9th, with 3.7 million residents in affected areas.
* Iowa ranked 10th, with 3 million residents in affected areas.

Other states has large numbers of people living in areas with smoky conditions.

“Families can lessen the health risks from smoke by staying indoors or limiting outside physical activity,” Knowlton said. “You can keep smoke levels low inside the house by closing the windows and running the air conditioner on ‘recirculate.’